This invention relates to an improved process for regeneration of a loaded scrubbing agent in a regeneration column equipped with a bottom heater and an overhead condenser, and in particular to a process comprising utilizing a vapor other than the pure scrubbing agent for stripping purposes. In such processes, stripping vapor is condensed in the condenser, the stripped components are removed and the remaining condensate is recycled to the regeneration column.
In many chemical and physical gaseous absorption processes regeneration is conducted by stripping with a vapor, which, for example, is produced by vaporization of a component contained in the scrubbing agent. In practice, for this purpose water contained in the loaded scrubbing agent is mostly used, but other fluids, such as, for example, methanol or hydrocarbons are also possible. In this case, the regeneration usually is performed in a regeneration column made up of two sections. The lower section is the actual regeneration section, while the upper section is used for rescrubbing of entrained scrubbing agent carried along by the stripping vapor. The loaded scrubbing agent is fed between the two sections, with the vapor necessary for the stripping being produced by heat at the bottom of the column. After condensation of the vapor in the head condenser, the components stripped from the scrubbing agent are removed in the gaseous form. The remaining condensate is fed as reflux to the upper part of the regeneration column and, after passing through this section, is mixed with the loaded scrubbing agent.
A partial stream of the condensate is often removed and used for rescrubbing of the scrubbing agent at the top of the scrubbing column. After passing through this upper section, the condensate also is mixed with the scrubbing agent.
Mixing of the condensate with the scrubbing agent is unsatisfactory inasmuch as the mixture has a higher boiling point than the pure condensate and boils at variable temperatures. It is also disadvantageous that by ad mixing of the condensate, the temperature in the actual regeneration section becomes substantially lower than without the mixing, and as a result the regeneration of the scrubbing agent is made unnecessarily difficult.